An example of this type of machine installation is, in particular, the multi-cylinder turbo set of a steam-generating plant, the machine parts comprising the individual turbine units and the generator.
The replacement of a machine part, whether planned or as the result of an accident, is an extremely time-consuming and thus, as a consequence of the long shut-down periods involved, a very cost-intensive operation. Even when the machine parts to be replaced are already stored on site in the form of replacement units, their initial assembly in particular and their alignment and testing all tell in terms of time.
If, in addition, system-related changes are to be made to the existing foundations, it may happen, for example in a nuclear installation, that the time required for this is greater than the shut-down time envisaged for the periodic replacement of fuel elements.